T.O. 33B-1-11-38(1)Immerse both panels n the working bath penetrant and allow them to drain for 10 minutessupported at an angle from the horizontal of approximately a 60° (15 ).(2)Process the first panel through a 10-second pre-rinse, 10-second drain, 20-second immersion inremover, 5-second drain, and 10-second rinse.(3)Process the second panel through the same cycle except double the immersion time in theremover.(4)Examine the panels under black light.(5)Clean the panels.b. When the remover is fresh and uncontaminated, neither panel should exhibit any backgroundfluorescence. As the penetrant level in the remover starts to build up, the short immersion time panelwill begin to show some residual fluorescence while the longer immersion panel remains free ofbackground. As the amount of penetrant in the remover continues to increase, the level of fluorescenceon the short immersion panel stabilizes and the longer immersion panel begins to show some residualbackground. When the remover reaches its penetrant tolerance limit, there will be negligible differencein fluorescence background on the two panels. The remover SHALL be changed at this point.Rejuvenation by partial extraction and addition of fresh solution, as with lipophilic emulsifiers, SHALLNOT be permitted due to the inability to control concentration.c. If the performance check in paragraph 1.5.5.4.1.2a does not indicate remover degradation, determine ifpenetrant is causing the background fluorescence by proceeding as follows using the same panels.(1)Immerse both panels in the working bath penetrant and allow them to drain for 10-minutes at a60° (±1°) angle.(2)Process the first panel using a 10-second pre-rinse, 10-second drain, 30-second immersion in theworking bath remover, 5-second drain, and a 10-second rinse.(3)Process the second panel using the same procedures above, except using the reference remover.(4)Examine the panels under a black light.(5)If background fluorescence is present on both panels, the working bath penetrant is contaminatedand must be replaced. If the panel processed with the reference remover is free of backgroundfluorescence, and the other panel exhibits any background fluorescence, then the determinationcan be made that the working bath remover has reached its penetrant tolerance limit and SHALLbe changed.(6)Cleaning the panels is mandatory.1.5.5.4.2SpraySolution.1.5.5.4.2.1Spray remover solutions are normally only used once with the effluent being disposed of after contact with the part.Contamination of the working solution is not a problem. However, the aspirator injection system, while simple andinexpensive, requires frequent checks to assure that the proper concentration is produced. Concentration of remover inthe spray SHALL be measured whenever the aspirator or water pressure valve is adjusted and at the intervals prescribedin paragraph 1.5.1.5. Measurement SHALL also be made whenever there is an unexplained change in backgroundfluorescence.